tag:blogger.com,1999:blog-5854741938955568545.post5050008552589897776..comments2024-03-26T01:53:19.600-07:00Comments on ElectricRCAircraftGuy.com--RC, Arduino, Programming, & Electronics: Propeller Static & Dynamic Thrust Calculation - Part 1 of 2Gabriel Stapleshttp://www.blogger.com/profile/10071071884455787806noreply@blogger.comBlogger98125tag:blogger.com,1999:blog-5854741938955568545.post-60157738886610623812023-06-17T13:36:29.052-07:002023-06-17T13:36:29.052-07:00Future questions and comments may optionally be le...<b>Future questions and comments may optionally be left on my newer website via GitHub here, where we can pick up the discussion: <a href="https://gabrielstaples.com/propeller-thrust-articles/" rel="nofollow">GabrielStaples.com: My propeller thrust articles</a>.</b> <br /><br />You'll need to create a GitHub account to leave a comment there, but it's worth it. We can edit comments there and have a much better conversation there.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-35557663176648037532022-10-13T07:20:27.606-07:002022-10-13T07:20:27.606-07:00Hi Jayesh, you don't use static RPM as the inp...Hi Jayesh, you don't use static RPM as the input for dynamic thrust. You use <b>dynamic</b> RPM. In other words, you must be measuring RPM in-flight, live, in real-time, in addition to V0 (forward airspeed), to calculate dynamic thrust live while flying or in a wind tunnel. <br /><br />V0 can be measured with a static-pitot tube, or estimated with a GPS, and dynamic thrust can be measured with an Arduino Uno, a few resistors and clipping diodes, and some advanced embedded software skill. <br /><br />To measure RPM live: for a brushless motor, connect your Arduino Uno or Nano GND to battery GND. Connect a single wire to any one of the 3 motor phase wires, through a clipping circuit to drop the voltage safely down to < 5V, and connect that to Pin 8 (input capture pin). Use input capture and interrupts to digitally filter out the PWM throttle pulses so you are just left with the trapezoidal commutation waves. The RPM is a function of the number of permanent magnetic poles in the motor and the commutation frequency. I mention this also at the bottom of my answer here, where I show an oscilloscope screenshot of what a motor phase pulses look like on a brushless motor. Search my answer for "brushless motor": <a href="https://stackoverflow.com/a/72724753/4561887" rel="nofollow">Stack Overflow: Physics-based controls, and control systems: the many layers of control</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-84131114840416982962022-10-13T04:34:21.322-07:002022-10-13T04:34:21.322-07:00Can I know the reason of using static RPM as input...Can I know the reason of using static RPM as input for dynamic thrust? Jayeshhttps://www.blogger.com/profile/13745189151030795916noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-61344303622649062222020-06-20T20:07:36.543-07:002020-06-20T20:07:36.543-07:00Yes, see this comment here. Also, see the "Fe...Yes, <a href="https://www.electricrcaircraftguy.com/2013/09/propeller-static-dynamic-thrust-equation.html?showComment=1384186445124#c1552390837172533197" rel="nofollow">see this comment here</a>. Also, see the "Feedback/Corrections/Contact me" link at the very top of this site.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-88684738261446869702020-06-20T19:58:18.765-07:002020-06-20T19:58:18.765-07:00You mean, did I write a paper? No, just these post...You mean, did <b>I</b> write a paper? No, just these posts online here. Are there academic papers referencing my work here? Yes, dozens I believe. Here are a few of them which show up on Google Scholar search results, for instance: <a href="https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=%22gabriel+staples%22+propeller+thrust&btnG=" rel="nofollow">Google Scholar search for '"gabriel staples" propeller thrust'</a>.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-3241996702827428842020-06-20T01:04:55.114-07:002020-06-20T01:04:55.114-07:00Johttps://www.blogger.com/profile/12775041491239383328noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-64510273761639214002020-06-19T11:18:45.839-07:002020-06-19T11:18:45.839-07:00do u have an email that can be contacted? thanksdo u have an email that can be contacted? thanksJohttps://www.blogger.com/profile/12775041491239383328noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-22971905834152895082020-06-19T11:18:07.942-07:002020-06-19T11:18:07.942-07:00Hi sir
Is there any paper which use equation with ...Hi sir<br />Is there any paper which use equation with diameter, pitch, and rpm as an input to find the thrust?Johttps://www.blogger.com/profile/12775041491239383328noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-87347333177865972352019-05-28T13:19:33.470-07:002019-05-28T13:19:33.470-07:00@Unknown, simply search this page's comments f...@Unknown, simply search this page's comments for my previous answer to someone: "From the aircraft's perspective, negative thrust is simply considered to be drag."Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-60006650116767564302019-05-28T11:53:15.221-07:002019-05-28T11:53:15.221-07:00What does that negative dynamic thrust means ??What does that negative dynamic thrust means ??Anonymoushttps://www.blogger.com/profile/06977000781998265794noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-43099391621948288132018-08-05T19:08:49.356-07:002018-08-05T19:08:49.356-07:00The links you provide show both are correct.The links you provide show both are correct.Nikhttps://www.blogger.com/profile/07781657524402543545noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-58603322325878198232018-08-05T18:33:35.084-07:002018-08-05T18:33:35.084-07:00Hi, several years late to the party!
Correct me if...Hi, several years late to the party!<br />Correct me if I'm wrong but I'm pretty sure motor torque = current / Kv. So if you're collecting data using a motor with a known Kv, finding torque is as simple as reading current draw, no?Nikhttps://www.blogger.com/profile/07781657524402543545noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-82923372212356976032018-08-01T23:40:32.019-07:002018-08-01T23:40:32.019-07:00I need to know more about the equation. Can i get ...I need to know more about the equation. Can i get your mailid?Ms. Uhttps://www.blogger.com/profile/03902739710855493652noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-37427346068941945782018-07-27T20:24:47.530-07:002018-07-27T20:24:47.530-07:00*I believe one of your early steps has a flaw*I believe one of your early steps has a flawAnonymoushttps://www.blogger.com/profile/16178091206298689906noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-75271449244044700362018-07-27T20:23:56.487-07:002018-07-27T20:23:56.487-07:00One of the early steps of your derivation has a fl...One of the early steps of your derivation has a flaw. Propeller thrust should be derived as <br />F = 0.5 * A * p * (Ve^2 - Vac^2)<br /><br />Sources:<br />https://www.grc.nasa.gov/WWW/k-12/airplane/propanl.html<br />https://www.grc.nasa.gov/WWW/K-12/airplane/propth.htmlAnonymoushttps://www.blogger.com/profile/16178091206298689906noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-54661226674424936612018-04-18T08:57:40.416-07:002018-04-18T08:57:40.416-07:00No, sorry, I haven't written any journal paper...No, sorry, I haven't written any journal papers on this. I did it all outside of school and normal work while I was a researcher in an indoor flight lab, but it hasn't been published in any journal. You are welcome to use it obviously but you'll have to just cite my name and website since there's no journal publication to cite for it.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-11509819541716898542018-04-04T08:15:52.917-07:002018-04-04T08:15:52.917-07:00Have you done any journal paper relating to this. ...Have you done any journal paper relating to this. I would like to cite your work in my senior college design project.Anonymoushttps://www.blogger.com/profile/02211408032035268136noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-417393323599233182018-03-23T08:59:32.828-07:002018-03-23T08:59:32.828-07:00No, sorry, but if you read my Part 2 article you&#...No, sorry, but if you read my Part 2 article you'll see that the 1.225 in the equation is the density of air in kg/m^3. Maybe you could try replacing that with the density of water, but I haven't done any experiments to see if that gives good results. Remember also, my equation assumes you *know* the RPMs. In other words, I originally planned on using it in-flight where you can measure live RPMs but don't have a thrust stand. Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-66554595541533335212018-03-16T23:23:57.329-07:002018-03-16T23:23:57.329-07:00I need help for underwater propeller calculations....I need help for underwater propeller calculations. Do you have any material regarding it?Anonymoushttps://www.blogger.com/profile/11717986800907432899noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-78074440031593985982018-02-24T14:40:13.570-08:002018-02-24T14:40:13.570-08:00Try this calculator: https://rcplanes.online/calc_...Try this calculator: <a href="https://rcplanes.online/calc_motor.htm" rel="nofollow">https://rcplanes.online/calc_motor.htm</a>Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-20464123422240884072017-10-22T22:41:34.388-07:002017-10-22T22:41:34.388-07:00Hi Gabriel! Thanks a lot for this beautiful resear...Hi Gabriel! Thanks a lot for this beautiful research! Its a piece of art! It is guiding me through my college's senior design project. I do have one question however: Could you guide me as to how to calculate the thrust for a 3-blade prop? My project involves a air-water convertible drone. The back prop is a 3 blade rc boat prop with 3"x5.5. Anonymoushttps://www.blogger.com/profile/05544872173767256550noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-65454157063771405812017-10-20T14:09:21.178-07:002017-10-20T14:09:21.178-07:00Yes, actually there is! Please provide me links an...Yes, actually there is! Please provide me links and data to your results and papers you write or publish. I'd like to see what you conclude from your work, especially if you do any dynamic thrust work in a wind tunnel or via flight test or something. You can find my email via the "Contact Me" tab at the top of my website.Gabriel Stapleshttps://www.blogger.com/profile/10071071884455787806noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-36599976919902727402017-10-19T15:27:53.622-07:002017-10-19T15:27:53.622-07:00By the way, I am doing my graduation project on ca...By the way, I am doing my graduation project on calculating and measuring the thrust force of propellers... If there is something I could do for you, I'd gladly doAnonymoushttps://www.blogger.com/profile/00936632462368219561noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-19567224250243322072017-10-19T15:22:09.713-07:002017-10-19T15:22:09.713-07:00Coooooooool!!! I liked your thinking very much Gab...Coooooooool!!! I liked your thinking very much Gabriel. Also special thanks for replying in just 10 minutes :)Anonymoushttps://www.blogger.com/profile/00936632462368219561noreply@blogger.comtag:blogger.com,1999:blog-5854741938955568545.post-31719880297061322022017-10-19T15:20:56.631-07:002017-10-19T15:20:56.631-07:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/07250216977650649700noreply@blogger.com